debug loop-detect level

device# debug loop-detect level 1

Strict mode:

Topology: port 1/1/25 is single port.
device# debug loop-detect level 3
Configure loop-detection on port 1/1/25 :
device(config-if-e1000-1/1/25)# loop-detection
device(config-if-e1000-1/1/25)# Loop-detection: port 1/1/25 (vlan=1), put into
errdisable state

Loose mode:

Topology: port 1/1/31 is connected to 1/1/32 in same vlan.

Configure loop-detection on port vlan 2 :
device(config-vlan-2)# loop-detection
device(config-vlan-2)# Loop-detection: port 1/1/31 (vlan=2), put into errdisable
state
Loop-detection: port 1/1/32 (vlan=2), put into errdisable state